- add an internal specific JNI function (javaCStringToUtf8()) to perform the UTF-8 conversion
- the SDK is configured to enable/disable the use of javaCStringToUtf8()

- previously the random seed was seconds based, and it could originate identical identity keys for different OlmAccount

- for 32bits platform target
- when debug flag is not defined

- remove compiler warnings when logs are not enabled
- new getInstanceId() function to refactor code

- Introducing namespace AndroidOlmSdk
- Fix logs (function names mixed up)
- Add new check based on the calling java object instance type (IsInstanceOf())
- Fix return value for getXXXInstanceId() in case of failure. Now 0 is returned.

- Modify constructors for inbound and outbound group sessions
- Add new Ecxception class

- Simplify JNI function signatures definition (Account & Session)

- review comments header
- refactor utility functions

 - new file olm_utility.cpp to have a stand alone function to initialize/alloc a random buffer
 - new class OlmMessage
 - complete OlmSession API with encryptMessage()
 - comments review
 - OlmAccount unit tests are green
 - new gradle to compile the shared lib according to debug mode